The present invention relates to field devices of the type used to control or monitor industrial processes. More specifically, the present invention relates to an industrial process field device having a discrete input and a discrete output.
Industrial processes are employed in the monitoring or manufacturing of process materials and fluids such as oil, paper pulp, etc. In order to monitor operation of an industrial process, process variable transmitters are employed. The process variable transmitters measure process variables and transmit the process variable information to a centralized location. Example process variables include flow rate, temperature, pressure, fluid level, etc. The process variable transmitter is one example of a field device. Another example field device is a controller. The controller is used to control operation of the process by actuating a control element. For example, the controller can adjust the position of a valve, change the speed of a pump, change the temperature of a heating element, etc. The controller may receive its instructions from a centralized location.
Typically, the field devices rely on wired communication to a central location. Example wired communication techniques include two-wire process control loops in which both power and information are carried on the same two wires. However, more recently wireless communication techniques have been employed with field devices. One example wireless communication technique is set forth in the Wireless HART® communication protocol in accordance with the IEC 62591 Standard.